The present invention relates to tools used by plumbers in residential and commercial building construction, and more particularly, to a device which may be readily mounted over the closet flange of a drain pipe normally used to support a toilet bowl flange in order to seal the pipe for pressure testing.
The use of mounting or closet flanges for toilet bowls on drain or discharge sewer pipes in both residential and both commercial construction is well known. See for example U.S. Pat. Nos. 3,181,585; 3,339,215; and 4,090,267. For many years, the closet flange and drain pipe were manufactured as one integral unit made of cast iron. More recently, so-called "drain/waste/vent" (DWV) pipe made of ABS (Trademark) plastic has been extensively utilized. A standard plastic DWV vent pipe is available with an integral closet flange.
The typical closet flange includes two opposed semi-circular slots on the flat receiving surface of the flange, which allow for insertion and then tightening of bolts perpendicular to the surface. Some closet flanges are also provided with diametrically opposed outwardly opening slots in the flange for receiving bolts. This was the typical configuration of the earlier cast-iron closet flanges.
A continual problem which has been faced by plumbers is the proper installation and mounting of drain pipe early in construction, long before the toilet bowl is mounted in place. Some plumbers cover the closet flange opening with duct tape, paper, burlap or anything handy which is easily dislodgable. As a result, debris from construction frequently goes through the opening in the closet flange and into the drain pipe, causing plugging. Since the closet flange is on the floor of the building, debris almost always accumulates in the pipe. The flange openings and the face of the closet flange can become encrusted with tile grout. Cleaning is time consuming and expensive and the closet flange can be broken or damaged.
U.S. Pat. No. 3,846,851 describes a closet flange which incorporates an integral knockout plug. However, there is a chance that the flange can be damaged in the removal of the plug. Also, the knockout plug can fall down into the drain pipe causing plugging. The flange is still subject to damage before the toilet bowl is mounted thereon.
Another problem continually faced by plumbers relates to pressure testing of the sewer system in a building. Most municipalities have a plumbing code, such as the Uniform Plumbing Code (UPC), which requires that the sewer pipe system in a residence or commercial building be capable of withstanding a predetermined internal pressure, between about five pounds per square inch and fifteen pounds per square inch, without any apparent leaks. In order to accomplish such a pressure test, it is necessary for each drain pipe terminating in a closet flange to be sealed. Standards set by the International Association of Plumbing and Manufacturing Offices (IAPMO) prohibit internal threading of the drain pipe portion adjacent the closet flange. Therefore, it is not possible to seal the hole in the closet flange with an externally threaded plug.
There have been several approaches for sealing a closet flange in order to accomplish a pressure test, but each of these approaches is expensive and, in some cases, time consuming. One approach is to insert an elastomeric ball into the drain pipe and to inflate the same to accomplish a seal. These inflatable plugs are expensive and the inflation thereof is both time consuming and dangerous. Over-inflation can lead to explosions, which can injure the plumber. An inflatable seal only seals the inside of the pipe, and does not test the joint between the pipe and the closet flange. An alternate approach is to glue a seal into the hole in the closet flange leading to the drain pipe. However, once the pressure test is complete, this seal must be broken out, and frequently lodges in the drain pipe, causing plugging. Furthermore, the knocking out of a plug which has been glued into place can damage the closet flange.
Another approach to pressure testing of a drain pipe connected to a closet flange is to manufacture a closet flange with an integral breakout seal as indicated above. However, these seals often become lodged in the drain pipe when they are broken out. Therefore, many municipalities are considering banning closet flanges with breakout seals. Yet another approach to sealing the hole in the closet flange is to utilize a so-called "dollar plug". This plug has a large wing nut which is turned by the plumber in order to expand an elastomeric sleeve against the internal walls of the drain pipe adjacent the closet flange. These dollar plugs frequently fail to provide an effective seal, and they are time consuming to install and remove. Also, repeated use of dollar plugs is sometimes impaired because they rust and become encrusted with grout and other debris. The dollar plug frequently does not allow the seal between the pipe and the closet flange to be tested.
U.S. Pat. No. 4,233,697 of Cornwall discloses a protective cover or cap 10 for toilet mounting flange 14 which is installed on a drain pipe 21. The cover 10 is comprised of a disk-shaped plate 11 with tubes 12 that extend upwardly from plate 11 which has a lower surface 11a to mate with the flat toilet bowl surface 13a. A flat elastomeric disk-shaped ring seal 15 is provided to seat between surfaces 11a and 13a and can be either separate or attached to the flange 14 or the cover 11. The bolts 18 which are ultimately used to attach the toilet bowl to the mounting flange 14 are protected in the tubes 12. Cornwall's device is designed to hydrostatically test the toilet bowl mounting flanges to determine if there are any leaks in the flange or in the drain pipe. The preferred embodiment in shown in FIGS. 2 and 3, which discloses the cover 100 having two tubes 118 with rectangular cross-section holes 119. The problem with Cornwall's device is that it is very difficult to attain a true seal when securing a flat disk with only two bolts. Tightening of the two bolts tends to cause the center of the disk to bulge, leaving gaps for leaks.
U.S. Pat. No. 2,559,210 of Bradley discloses a device, including a U-shaped strap 14 for holding a closet flange ring 10 firmly in place over the upper end of the drain pipe 11 during the pouring of concrete 12 around the drain pipe. Bolt and nut assemblies 22 and 23 extend through elongated slots 19 and 20 in the ring 10 and attach to opposite sides of the U-shaped strap 14. A generally cylindrical elastomeric member 32 may be radially expanded against the inner walls of the drain pipe 11 by rotating a wing nut 27 mounted above the center of the U-shaped strap 14. A threaded pipe 31 extends through a slotted portion in the center segment of the U-shaped strap 14 and through the center of the elastomeric member 32. The elastomeric member 32 is squeezed radially against the inner wall of the pipe 11 by turning the wing nut 27 in order to squeeze the elastomeric member 32 between bearing members 28 and 35. When the elastomeric member 32 is squeezed against the inner wall of the pipe 11, the device forms a test plug. The U-shaped strap 14 is not an anchor for the test plug, but rather is held in place by the test plug. The device Bradley is thus very similar to the conventional dollar plug described above. It is difficult and time consuming to install. Significant torque or tightening on wing nut 27 is required. This device may be difficult to repeatedly use because of the build up of debris on the threaded pipe, and because the mechanical components of this device may rust over a long period of time.